Mailbox flags are well known. Automatically positioning the flag of a mailbox in an upward position, after box opening, has been proven desirable in alerting a user of postal delivery. The designs of the devices for automatic flag pivot upon door opening differ greatly, though. Most devices require alteration or modification of a mailbox in order to fit a pivoting flag mechanism. However, it is not desirable to drill holes in a mailbox to mount a pivoting flag device. Further, flag devices which require drilling through the side of a mailbox are prone to loosening and failure. It is further undesirable to affix a pivoting mechanism by encircling a mailbox, especially those which negate full mailbox circumference access. It is also undesirable to propose the use of complexly designed automatically pivoting flag devices, as lack of reliability and production expenses are quite real. What is needed is a mailbox flag which can be positioned in a horizontal position, then provides automatic vertical flag positioning upon mailbox door opening. The present apparatus provides this in a single unit mechanical combination which requires no drilling or any other alteration or modification of a mailbox.